“Consider this brief excerpt from the National Institute of Justice’s Publication, Selection and Application Guide to Personal Body Armor

The first step in selecting the appropriate protection level of body armor is to establish the level of protection that users need based on the realistic weapon threat they face. To date, body armor has not been known to fail to prevent the penetration of a bullet constituting a threat equal to or less than the protection rating of the armor. However, officers have died from wounds received from weapons or ammunition exceeding the rated protection of the armor.”